Saturday, December 06, 2008

So just as I start to blog a tiny bit, I'm disappearing again for another work trip (and a bit more). This time it's off to Cape Town (well, Stellenbosch, really) for a workshop on "Applications of Gauge/Gravity Duality". It'll be me and a lot of string theorists, where naturally I'll be the token experimentalist. Still, should be a blast in a beautiful place -- and hopefully I'll learn a thing or two, and teach a thing or two. In any case, it's great to have a chance to spread the RHIC gospel. More later.

Thursday, December 04, 2008

Yesterday, a friend of mine who works for the Cullman Center for Scholars and Writers asked my wife and me to be her guests to hear Lauren Redniss, an artist and writer (nominated for a Pulitzer for her NYTimes Op-Art pieces). It felt like something out of a mysterious teen novel to go to the NY Public Library, amble up the stairs gawking at the high ceilings and stone work, and have to knock to gain entry to the conference room (where they nicely served Dominican food for lunch).

Redniss, who has written/drawn about dancers and chess and people and their lives in New York, is tackling the lives of Pierre and Marie Curie who did pioneering studies in radioactivity (and Marie even coined the term). It is an interesting approach, trying to tie various aspects of their lives to the science they devoted themselves to (and devote themselves they did -- sounds like they didn't get out of the lab much!).

Pierre Curie died in a freak accident in a Paris street, where he tripped and had his skull crushed by a heavily-laden horse-drawn carriage. Redniss related this to the concept of the "normal accident", one which occurs in complex, tightly coupled systems, where one seemly-trivial problem may randomly coincide with another, and their combination may trigger a catastrophe. Turns out that Three Mile Island is the paradigmatic case, a fact that Redniss interestingly ties back to the Curies -- their work having made nuclear power (eventually) possible. She also connected it to the randomness of radiation itself.

The thing that struck me about that latter point was that the randomness of life and the randomness of radioactive processes aren't really the same. The randomness of life is one that emerges out of complex environments, like cities, where many people and things move according to their own agendas and interact (physically, socially, etc). Getting hit by a car is the result of a long causal chain which brought you to that crosswalk, and a different causal chain which brought the car there at the same exact time, and then perhaps another factor which makes you cross against the light etc. The point here is that there is a long, confusing, but nominally well-defined set of events that could in-principle be reconstructed to explain why that accident occurred where and when it did.

But radioactivity (and indeed any quantum mechanical system) is different. As far as we know, quantum mechanical processes like nuclear decay just happen when they happen, and completely at random. The life or death of Schrodinger's cat, and the mystery of the thought experiment relies on this truly random nature of quantum processes. All attempts to reduce quantum probabilities to the deterministic activity of hidden degrees of freedom have failed (see e.g. Bell's Theorem). Thus for all practical purposes, radioactivity is one of the purest examples of irreducibly random behavior existing in nature, and this is no small thing: generating random numbers with computers (e.g. pick a number between one and ten) is a non-trivial thing, and most only make "pseudorandom" numbers at best.

Anyway, I did manage to ask if she had considered this difference in her thinking-through of the story she was trying to tell. Of course I also managed to say that radioactivity was the "only" way that such randomness was manifest in nature, which is obviously wrong. Luckily the roomful of writers, historians, and graphic designers didn't catch me right off. Too bad that a well-known historian of science was also in the room, who did!